The signals are either in phase, mono or summed to center in the frequencies that would normally be sent to a subwoofer.
Of course you can. A million of these things out there. Never heard of one dying because of out of phase bass. Can only imagine what out of phase bass might do to your stylus.
See above. You guys are worrying about the wrong things.
Nice thanks for the help everyone.
Basically this is how I want the setup:
Right channel: Main amp with sub woofer out > Internal amplifier in the sub > low level crossover > rightside voice coil
Left channel: Main amp with sub woofer out > Internal amplifier in the sub > low level crossover > leftside voice coil
I did assume this but due to this post: I thought otherwise!
Basically this is how I want the setup:
Right channel: Main amp with sub woofer out > Internal amplifier in the sub > low level crossover > rightside voice coil
Left channel: Main amp with sub woofer out > Internal amplifier in the sub > low level crossover > leftside voice coil
I did assume this but due to this post: I thought otherwise!
Looks like you might have made a mistake here?
Crossovers for post-amplifier use for subwoofers are often big and expensive. Ones for before the amplifier are small, but you need the extra amplifier.
As soon as you start tweeking the crossover, the active design is immediately cheaper, as those components cost pennies, not pounds...
I think bass is mono to from 80Hz down on most CD recordings, though I have heard ones where the bass is panned to one side (this was when stereo was new and exciting). This wouldn't be a problem as one of the amplifiers would sit and do little while the other drivers the speaker.
Chris
PS - you're unlikely to cook the coils anyway. Most speakers are surprisingly resilient.
I'm getting more confused. Seems real strange or maybe I don't understand.
Why two amps to drive one driver? Why not have the voice coils in series?
Why not electronic crossover ahead of the woofer "plate" amp? That's much better for a whole bunch of reasons.
Footnote: now that I've been thinking about it, it does seem a poor concept to have two voice coils tugging in slightly different directions on one former even if their sum is nominally the output you want and mostly correlated (and folks have been doing this for decades with no failures that I've read about... or that anybody has been able to detect by ear).
Why two amps to drive one driver? Why not have the voice coils in series?
Why not electronic crossover ahead of the woofer "plate" amp? That's much better for a whole bunch of reasons.
Footnote: now that I've been thinking about it, it does seem a poor concept to have two voice coils tugging in slightly different directions on one former even if their sum is nominally the output you want and mostly correlated (and folks have been doing this for decades with no failures that I've read about... or that anybody has been able to detect by ear).
Have you ever looked at a lowpassed signal on a XY scope?
sub 80Hz are often out of phase, varying in strength and doing any other type of pirouette.
You can not assume the bass signal to be mono because it is simply not true in reality. Many say it should but I have seen numerous new recordings with varying content between the channels.
Sure many do have mono content in the bass region but even in those recordings they are differences.
Sending each half of a stereo signal to a DVC driver will cause unexpected things to happen.
Take a for example a simple pan. One VC will start with the full signal and one with nothing.
First of all you are now using half the motor strength. Second you are dissipating a lot of back EMF into the other channel.
At the middle if the pan you VCs are working together giving full strength.
This will give different Qes and BL through the pan.
Now a pan might not happen like that but much content bounce around at times and I would expect the sound to change to the worse.
Electronic music should have the habit to sum it to center right?
Well I guess not as I see a lot of O, ah and squiggles.
Using two amps to power a DVC is fine. Just make sure the signal is the same.
A changeover switch goes there. SEL is the selecting bit, NOR is to route normal-phase signals and INV is to route inverted-phase signals.
Bypass any potential problems by feeding both amps with the same signal. (summed to mono and low passed).
David, perhaps look at it from an artist's/recording studio's point of view. Most "hifi"s are small affairs, often put on a shelf. There would be no point what so ever in including bass that was out of phase between channels, as it would simply cancel out, and not be reproduced. That's also why few bother with low bass (<40Hz) any more - 99% of systems won't reproduce it.
You say there's differences between the channels where it's summed to mono. How have you tested this? Exactly how much difference is there?
bentoronto, I shall try flicking between mono and stereo, see if anything turns up...
David, perhaps look at it from an artist's/recording studio's point of view. Most "hifi"s are small affairs, often put on a shelf. There would be no point what so ever in including bass that was out of phase between channels, as it would simply cancel out, and not be reproduced. That's also why few bother with low bass (<40Hz) any more - 99% of systems won't reproduce it.
You say there's differences between the channels where it's summed to mono. How have you tested this? Exactly how much difference is there?
bentoronto, I shall try flicking between mono and stereo, see if anything turns up...
More than 99%. Maybe 99.9999%.
There may be "visual" differences but that's not the same as auditory differences - even little differences or insignificant phase/time shifts look big on a dual trace scope. But often look milder when viewed as an X-Y plot or unhearable by ear.
You may be able to detect a difference among two speaker mono, single speaker mono, and two speaker stereo (and maybe other permutations). But that isn't the same as picking which is best (I am ignoring the benefits of spacing woofers around your room). I've opted for one grand corner Kliipschorn rather than two wee boomy bass reflexes.
Mono button - but remember, you should be down the hall when testing.
"But often look milder when viewed as an X-Y plot or unhearable by ear."
The difference between L and R is not insignificant when viewed on XY scope. Many recordings leave you with a "circle" if you leave the decay time long enough.
You are welcome to test it yourself.
Soundcard Scope
Lowpass filters are built in if needed. Decay time is limited when using filters though.
"Bypass any potential problems by feeding both amps with the same signal. (summed to mono and low passed)."
That Is what I have been saying, but people insist that the signal is mono below 80Hz in all recordings which is simply not true.
I would love to test the difference but I don't have a DVC sub.
Remember we are NOT talking stereo vs mono subs here. That is a matter for another discussion.
The difference between L and R is not insignificant when viewed on XY scope. Many recordings leave you with a "circle" if you leave the decay time long enough.
You are welcome to test it yourself.
Soundcard Scope
Lowpass filters are built in if needed. Decay time is limited when using filters though.
"Bypass any potential problems by feeding both amps with the same signal. (summed to mono and low passed)."
That Is what I have been saying, but people insist that the signal is mono below 80Hz in all recordings which is simply not true.
I would love to test the difference but I don't have a DVC sub.
Remember we are NOT talking stereo vs mono subs here. That is a matter for another discussion.
Well, I did my own experiment about whether mono sounds different than stereo down the hall. Seems dumb not to know elementary things like this, but I just wasn't certain.
Anybody want to guess before I give the answer?
First of all, inside your music room, if you put yourself in some odd location like behind one speaker, there's no stereo illusion. Need I add "duh"? There is an obvious although not profound change in ambiance, of course. But barely the illusion of the Dudamel Simon Bolivar Youth Orchestra recorded by DGG - big stage stuff - you get at the sweet spot. Nothing at all like that sweet spot ambiance when listening in an odd location with a stereo feed or much less than the stereo feed ambiance when listening in mixed mono, at least in my fairly damped room.
Now down the hall 15 feet, there is a slight difference in sound but not like you'd care to prefer A to B really.
So I think that stereo channels are created to serve certain wonderful purposes at the sweet spot. But away from that seat, it is just squiggles on a scope and you can play left, right, stereo, or mix to mono and not much different to the listener who gets them after playing into a room down the hall (unless maybe the engineer is doing funny stuff).
Anybody else try this 2 minute "experiment" in mixing channels?
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